Calmagrostis canadensis (Michx.) Beauv. also known as bluejoint, is a grass plant that poses a serious threat to white spruce regeneration in reforestation areas. In cut-over. C. canadensis quickly spreads by means of rhizomes and seed to cover much of the site. The grass grows thick and tall thus out-competing white spruce for resources such as light, water and nutrients.
To date site preparation techniques and grazing have failed to control C. canadensis. Herbicides may be effective but their use has been extremely limited due to environmental concerns. Other weed species have been successfully controlled with plant pathogens., for example northern jointvetch by Colletotrichum gloeosporiodes f.sp. aeschynomene.
A variety of mycoherbicides have been proposed to control specific weeds. for example, Canadian Patent Number 1,224,055 (Watson et al, Jul. 14, 1987) describes the use of Colletotrichum coccodes for controlling velvetleaf and U.S. Pat. No. 4,643,756 (Cardina et al, Feb. 17, 1987) describes the use of C. truncatum for controlling Florida beggarweed. U.S. Pat. No. 4,776,873 (Caulder et al, Oct. 11, 1988) teaches a synergistic herbicidal composition comprising Altemaria cassiae and chemical herbicides for controlling sicklepod.
C. canadensis has been shown to be controlled by the microbes C. calamagrostidis, F. nivalis and mutants thereof. See commonly assigned U.S. Pat. No. 5,472,690. A drawback of this technology is that it is somewhat reliant on environmental factors such as free moisture on the leaf surface, for infection to occur.
The low temperature basidiomycete (LTB) fungus, was first described as a pathogen of C. by Lebeau and Logsdon (1958) Snow Mould of forage crops in Alaska and Yukon. Phytopathology, 48: 148-15. This fungus is psychrophilic and will only grow and parasitize plants under a snow cover. It is native to the boreal forest and so is not considered an introduced species. The fungus is not known to produce spores but spreads by vegetative growth.
Bio-control of C. canadensis and other related monocot species which are known to be hosts of LTB through use of the LTB fungus presents a good opportunity for controlling these grasses. The fungus does not necessarily have to kill the grass for it to be effective as reduced growth of grass plants would allow white spruce seedlings time to grow above the grass canopy.
Some preliminary work by our group with low temperature basidiomycete (LTB) fungii was described in Bio-control of bluejoint grass (Calamagrostis canadensis) using low-temperature basidiomycete (LTB) K. A. Schreiner et al, Canadian Journal of Plant Pathology, volume 17, 1995. There is no description in this abstract of the selected LTB strain, the delivery composition, or the delivery method according to the invention.